544 



rivers now hollowing out courses for themselves, have exposed, in many 

 places, the skeletons of those ancient inhabitants of the neighbouring 

 land. 



Mr. Darwin then briefly alluded to a small formation of mud and 

 shingle at Bahia Blanca, some hundred miles south of the Plata, in 

 which the remains of several extinct quadrupeds have been dis- 

 covered. Amongst these he enumerated the Megatherium Cuvieri, the 

 remains perhaps of a smaller species of Megatherium ; a quadruped 

 closely allied to the armadilloes, but nearly as large as a horse 5 some 

 small rodents, and other animals. These remains are embedded with 

 one species of terrestrial, and several of marine shells, the latter 

 being identical with some existing in the adjoining bay. It is, there- 

 fore, certain that the greater number of the above mammalia found 

 at Bahia Blanca lived within a very recent epoch ; and from the po- 

 sition of the bed in which they occur, it is equally certain that the 

 form of the land has undergone, since that period, very little change, 

 even of level, with respect to the ocean. 



Several hundred miles further southward, Mr. Darwin found the 

 remains of an animal which Mr. Owen says has an affinity with the 

 Llama or Guanaco, but was of a gigantic size : this animal likewise 

 existed since the Atlantic has been peopled by the shells now living. 



The author observed in conclusion, that the comparative recent- 

 ness of the epoch at which the fossil mammalia lived, is shown, first 

 by the shells associated with them j secondly, by the recent tertiary 

 character of the strata underlying the deposit containing those re- 

 mains ; and thirdly, from the little altitude of such beds above the 

 level of the sea 3 for in this country, according to the author's obser- 

 vations, the movements seem to have been so regular, that the amount 

 of elevation becomes a measure of time. 



These facts relating to the former existence of the inhabitants of 

 a part of the globe so remote from Europe, fully confirm the re- 

 markable law, often insisted upon by Mr.Lyell, that " the longevity 

 of the species " among mammalia has been of shorter duration than 

 among molluscs. The author finally remarked, that although several 

 gigantic land animals, which formerly swarmed in South America, 

 have perished, yet that they are now represented by animals, confined 

 to that country ; and though of diminutive size, possess the peculiar 

 anatomical structure of their great extinct prototypes. 



An extract of a letter, dated Saharumpore, 18th November, 1836, 

 from Captain Cautley to Dr. Royle, was next read ; permitting the 

 announcement of a fact which had long been communicated to the 

 latter, of the finding of the remains of a quadrumanous animal in the 

 Sewaliks, or Sub-Himalayan range of mountains. An astralagus 

 was first found, but latterly a nearly perfect head, with one side of 

 the molars and one orbit nearly complete. The animal must have 

 been much larger than any existing monkey, and allied to Cuvier's 

 Cynocephaline group. Captain C. also announced the discovery by 

 Major Colvin of a specimen of the head of the Sivatherium, in which, 

 in conformity to the conjectures of Dr. Falconer and himself, in their 



